Claims that life or the potential for it exists on the Mars were boosted yesterday when scientists declared they saw the remains of a frozen sea on the planet's surface and speculated the ice may hold preserved organisms.Planetary geologists led by John Murray of Britain's Open University said the evidence comes from pictures sent home by the European Space Agency's Mars Express orbiter.High resolution, stereoscopic images reveal a flat, "plate-like terrain' in the region of southern Elysium Planitia, near the Martian equator, that appears remarkably like fields of pack ice on earth, they say.The "frozen lake' measures about 800 by 900 kilometres long and is probably about 45 metres deep on average, making it similar in size and depth to the North Sea.